/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.gaia.translation.wrappers.streaming.stableinput;



import com.bff.gaia.unified.sdk.transforms.DoFn;



import java.util.stream.Stream;



/**

 * A handler for buffering elements which cannot be processed yet because {@link

 * DoFn.RequiresStableInput} is used and a checkpoint is currently

 * pending.

 *

 * <p>When a DoFn is annotated with @RequiresStableInput we are only allowed to process elements

 * after a checkpoint has completed. This ensures that the input is stable and we produce idempotent

 * results on failures.

 */

interface BufferingElementsHandler {



  /** Returns all buffered elements. */

  Stream<BufferedElement> getElements();



  /** Adds the given element to the buffered elements. */

  void buffer(BufferedElement element);



  /** Clears buffered elements. */

  void clear();

}